Homoaconitate hydratase

In enzymology, a homoaconitate hydratase (EC 4.2.1.36) is an enzyme that catalyzes the chemical reaction

(1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate ⇌ (Z)-but-1-ene-1,2,4-tricarboxylate + H₂O

Hence, this enzyme has one substrate, (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate, and two products, (Z)-but-1-ene-1,2,4-tricarboxylate and H₂O.

This enzyme belongs to the family of lyases, specifically the hydro-lyases, which cleave carbon-oxygen bonds. The systematic name of this enzyme class is (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate hydro-lyase [(Z)-but-1-ene-1,2,4-tricarboxylate-forming]. Other names in common use include homoaconitase, cis-homoaconitase, HACN, Lys4, LysF, and 2-hydroxybutane-1,2,4-tricarboxylate hydro-lyase (incorrect). This enzyme participates in lysine biosynthesis.